Thomas a



(No Model.)

T. A. EDISON ELEGTRIG LIGHTING sYsTEM.

No. 265,776. Patented Oct. 10, 1882.

wamssw, I ave7ato 2";

- electric lamps arranged in multiple are.

UNITED STATES Y PATENT OFFICE.

THOMAS A. EDISON, OF MENLO PARK, NEW JERSEY, ASSIGNOR- TO THE EDISON ELECTRIC LIGHT COMPANY, OF NEWV YORK, N. Y.

ELECTRIC-LIGHTING SYSTEM.

Q SPECIFICATION forming part of Letters Patent No. 265,776, dated October 10, 1882.

Application filed Novemberll, 1881. (No model.)

To all whom it may concern:

Be it known that I, THOMAS A. EDISON, of Menlo Park, in the county of Middlesex and State of New Jersey, have invented anew and useful Improvement in Electric-Lighting Systems, (Case No. 354 and I do hereby. declare that the following is a full and exact description of the same, reference being had to the accompanying drawing, and to the letters of reference marked thereon.

The object- I have in view is to produce devices to be used in connection with dynamo or magneto electric machines and electric lights, which will notify the engineer when the lights are above or below the desired limit of candle power, so that he can regulate the generative capacity of the machine or machines in accordance therewith. These devices are especially adapted for use in isolated work, or with plants for lighting separate buildings or small areas, and in connection with incandescing This I object 1 accomplish by arranging an electromagnet in a derived or multiple-arc circuitfrom the main or consumption circuit, such magnetcircuithavingmanytimes more resistance than one of the lamp-circuits, a wire or other resist-= ance being placed therein for that purpose. An incandescinglamp may, however, be used for this resistance. In a shunt-circuit around this resistance are arranged the armature-lever of the magnet and a vibrating bell. The free end of the armature-lever plays between two contacts the making of each of which completes acircuit through the bell-hammer vibra tor. Between the armature-lever and the front contact is ayielding stop, which may be an arm held back against a fixed pin by a spring. This yielding stop-arm determines the central position of the armature-lever. One of these bellcircuits has considerably more resistance than the other, so that alarms varying noticeably in their loudness will be produced. When the lamps are within the fixed limits of candlepower the magnet will attract the lever sufliciently against the retraotile force of its spring to separate it from the back contact, and will hold it forward against the spring stop-arm, so as to open the bell-circuit. Now, if the current increases so as to raise the lamps above the limit of candle-power, the magnet will atthe same time be weakened and thelever will make the back contact. This completes the bell-circuit through greater resistance than when the front contact is made, and a continuous alarm will'be sounded, which will be noticeably i'eebler than in the instance first described. As soon as the lights are brought up to the desired degree of luminosity the alarm will cease to sound,the bell-circuit being broken by the attraction of the lever to a central position against the spring.

It is evident that, instead ofusing a single vibrating bell with two circuits having different resistance, two bells might be used, in which case the bell-circuits mi ghthave diflerentresistances, or the circuits could have the same resistance and the bells be constructed to give sounds of differentpitch,or both features could be combined.

Instead of bell-alarms alone, an indicator might be used consisting of a pointer traveling upon a scale to right or lelt, and operated by the armature lever of the electro-magnet in the multiplearc circuit, and in connection with the indicator an alarm could be arranged to strike when the pointer. reached a certain point on either side ofits normal position.

The foregoing will be better. understood by reference to the drawing, in which the figure is a diagrammatic view.

A represents a dynamo or magneto electric machine; 1 2, the main or consumption circuit, and a a incandescing lamps in multiple-arc or derived circuits.

3 4 represent a multiplearc or derived circuit from 1 2, having resistance It and the coils of an electro-magnet, B, placed therein. From 3 4 is a shunt, 5 6, around the resistance R. The armature-lever G, retracted by spring I), is in this circuit. Front and back contacts,

c c, are connected with the spring d of the vibrating-bell mechanism, which consists of electro-magnet c, armature-lever f, forming bellhammer, and gongg. Resistances R R are arranged in the bell-circuit, resistance B being in the circuit of each contact 0 0, while B? is only in the circuit of the back contact, 0. A yielding stop-arm, O, isplaced between lever G and front contact, 0, and is drawn back by a spring, b, against a fixed pin, D

The field-oi force circuit of the machine A may he a multiple-arc circuit, 7 8, from 1 2, and be provided with an adjustable resistance, R for regulating the generative capacity, as required by the sounding of the alarm.

The alarm described is useful with other translating devices besides lamps to show corresponding conditions.

What I claim is- 1. The combination, with one or more electrical generators, means for regulating such generator or generators, and electric lamps arranged in multiple arc, of an electrically-operated alarm or indicator for indicating prede-' termined limits above or below or both above and below the desired or normal condition of the current, and an electro-magnet located in a multiple-arc circuit and controlling the circuits of such alarm or indicator, substantially as set forth.

2. The combination, with one or more electrical generators,means for regulatingsuch generatoror generators, and electric lamps arranged in multiple arc,ofan electrically-operated alarm or indicator for indicating predetermined limits above or below or both above and below the desired or normal condition of the current, an electro-magnet located in a multiple-arc circuit, the armature-lever of such magnet, making and breaking the circuits of such alarm or indicator at its contacts, and means flor determining the'centra-l position of such armature-lever, substantially as set forth.

3. The combination of a main circuit, an electro magnet in a. derived circuit, and an armature-lever therefor, completing circuits at both its front and back contacts, resistances differing in amount, located in said circuits, and a vibrating magnetic alarm, substantially as set forth.

This specification signed and witnessed this 27th day of September, 1881.

THOS.,A. EDISON. Witnesses: H. W. SEELY, RIonD. N. DYER. 

